Polarized far-infrared emission from the core and envelope of the sagittarius b2 molecular cloud

Giles A Novak*, J. L. Dotson, C. D. Dowell, P. F. Goldsmith, R. H. Hlldebrand, S. R. Platt, D. A. Schleuning

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

We have detected linear polarization in the 115 μm continuum radiation from the giant molecular cloud Sagittarius B2. We found polarization at nine positions in the dense cloud core and at 15 positions in the less-dense envelope. The polarization in the core is due to absorption by magnetically aligned grains and that in the envelope is due to emission from magnetically aligned grains. The inferred magnetic field direction is roughly north-south everywhere, but with spatially smooth variations of up to 30°. By considering our data together with Zeeman splitting observations we are able to set a conservative lower limit of 150 μG on the strength of the large-scale field in the envelope. If large-scale fields this strong are common in Galactic center clouds, they could be detectable via large-beam Zeeman measurements. For positions in the envelope that are furthest from the core, the field is nearly parallel to the plane of the Galaxy. This is consistent with the idea of a globally azimuthal magnetic field in the Galactic center neutral gas layer, which is expected if gravitational forces dominate magnetic forces.

Original languageEnglish (US)
Pages (from-to)320-327
Number of pages8
JournalAstrophysical Journal
Volume487
Issue number1 PART I
DOIs
StatePublished - Jan 1 1997

Keywords

  • Dust, extinction
  • Galaxy center
  • ISM: individual (Sagittarius B2)
  • ISM: magnetic fields
  • Infrared: ISM continuum
  • Polarization

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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